Five friends P. O, X, Y and Z purchased some notebooks. The relevant information is given below: 1. Z purchased 8 notebooks more than X did. 2. P and Q together purchased 21 notebooks. 3. O purchased 5 notebooks less than P did. 4. X and Y together purchased 28 notebooks. 5. P purchased 5 notebooks more than X did. If each notebook is priced 40, then what is the total cost of all the notebooks?

As per the information provided in the question: Statement 1 -> Z = X + 8 ….(i) Statement 2 -> P + Q = 21 ….(ii) Statement 3 -> Q = P – 5 ….(iii) Statement 4 -> X + Y = 28 ….(iv) Statement 5 -> P = X + 5 ….(v) Total number of Books = P + Q + X + Y + Z Solving equations (ii) and (iii), we get: P = 13 Q = P – 5 = 8 Using above result and equation (v), we get: X = P – 5 = 8 Using above result and equation (i), we get: Z = X + 8 = 16 Using (iv), we get: Y = 28 – 8 = 20 So, P + Q + X + Y + Z = 13 + 8 + 8 + 20 + 16 = 65 So, total cost of all the notebooks = 65 × 40 = Rs. 2600